Journal of Ecological Engineering Volume 18, Issue 3, May 2017, pages 68–73 DOI: 10.12911/22998993/69351 Research Article THE REMOVAL INVESTIGATION OF COCONUT ACID SURFACTANTS IN ACTIVATED SLUDGE’S SYSTEM Baharan Moazzenipour1, Alireza Salehpour1, Batool Ahansazan2, Sohrabali Ghorbanian1, Hamid Rashedi1 1 School of Chemical Engineering, College of Engineering, University of Tehran, Tehran, Iran 2 Faculty of Engineering, Department of Chemical Engineering, Valiasr Technical College, Tehran, Iran * Corresponding author’s e-mail: [email protected] Received: 2017.01.28 ABSTRACT Accepted: 2017.03.07 There are significant municipal concerns relating to the use of surfactants and en- Published: 2017.05.02 zymes in the process of wastewater treatment. Treatment plants use different tech- niques to remove impurities from water.As wastewater treatment plants use the latest technology to remove contaminants from water, there are high costs, and sometimes an enforcement of regulations is lax. Still, many municipalities across the country prohibit the use of surfactants and enzymes entering wastewater treatment because of the harmful effects of these products on the sewer lines and high damage costs. Sur- factant compounds are organic. Their molecules include water-soluble and oil or an insoluble component. These molecular compounds seek the water surface and chemi- cally reduce the boundaries between oil and water. When surfactants are in the water, they absorb into the soil and can cause injury to plants and organic organisms, but people find surfactants and enzymes useful in cleaning agents for emulsifying and dispersing oil and grease. Scientists have found that at least some surfactants are toxic to ecosystems, people and animals, but they have not been able predict far-reaching consequences. And now the most important question is how to solve this problem or how to reduce these negative effects. In this paper we tried to remove surfactants from waste water with an activated sludge system. Keywords: Cocamide DEA, surfactant, waste water, activated sludge, COD. INTRODOCTION other cutaneous allergies were present. In both instances, Cocamide DEA was present in sev- Cocamide DEA, or Cocamide DI Ethanol- eral personal care products used by patients. In amine is a DI ethanol amide made by reacting the the third case, occupational exposure was sus- mixture of fatty acids from coconut oils with DI pected. Cocamide DEA is an unusual allergen Ethanolamine. It is a viscous liquid and is used as that may cause contact dermatitis in individuals a foaming agent in bath products like shampoos who often have multiple other skin allergies.The and hand soaps, and in cosmetics as an emulsi- International Agency for Research on Cancer fying agent (See Cocamide for the discussion of (IARC) lists coconut oil di ethanolamine con- the lengths of carbon chains in the molecules in densate (Cocamide DEA) as an IARC Group the mixture). The chemical formula is CH3(CH2) 2B carcinogen, which identifies this chemical n C(=O) N (CH2CH2OH)2, where n can vary de- as possibly carcinogenic to humans. In June pending on the source of fatty acids. 2012, the California Office of Environmental Three cases are reported by individuals al- Health Hazard Assessment added Cocamide lergic to Cocamide DEA, also known as coco- DEA to the California Proposition 65 (1986) a nut DI ethanol amide. In two cases, multiple list of chemicals known to cause cancer. 68 Journal of Ecological Engineering Vol. 18(3), 2017 MATERIAL AND METHOD Ammonium phosphate 0.34 gr/day and Ammo- nium nitrate 0.93 gr/day. The feeding was done Experiment for a week. So the culture was ready for testing. In this experiment we used 4 bubbling stirred reactors. Three reactors contained activated EXPERIMENTAL PROCEDURE sludge with surfactants (Cocamid DEA) with variance density 1000, 2000, 4000 ppm and the We used four reactors with the same structure forth one contained only activated sludge. and volume as explained above in parallel tests. We used activated sludge for their more ad- Experiments were started batch wise. Activated vantage; it is not expensive, does not have any sludge from wastewater treatment plant was add- danger for the environment and it is accessible. ed to the reactors as seed. The similar value of Activated sludge treatment is suitable for use in sludge was inoculated in four parallel reactors. facilities that contain organic chemical waste. The test reactors (R1, R2 and R3) contained bio These may include municipal sewage treatment surfactant. The Cocamid DEA bio surfactant con- plants, oil refineries, food processing plants and centration was added to them, in 1000, 2000, 4000 chemical manufacturing At the first day each of ppm respectively. In the control reactor (R4), the the surfactant’s reactors contained 4 gr of dry feed water did not contain any surfactant in or- matters with distilled water free from additive. der to specify the effect of surfactant. Each of the We aerated the reactors for 28 days. test series dissolve in distilled water and make up 1 litter. The entire reactor was aerated by an air Prepration of activated sludge pump. These conditions were fixed for the entire duration of the experiment. The temperature and Activated sludge culture was received from Pressure were 250 °C and 625 mm Hg and pH wastewater treatment plant of Oil National Com- adjusted to 7. A schematic diagram of the experi- pany in Tehran, Iran. The aerobic reactor was mental setup is shown in Figure 2. inoculated with this culture. The constituents of wastewater used throughout the studies are given in Table 1. Lack of each of these materials can Table 1. Inorganic constituents of microorganisms limit the growth of microorganisms, of course, Chemical Compounds Percent there are all of them in the wastewater, except MgO 8 phosphorus, nitrogen, carbon and oxygen are re- K2O 6 quired that were added every day. In the starting Fe2O3 1 test, first and second day the sludge settling time P2O5 50 was two hours then the dead cells were collect- SO2 15 ed. On the third day sludge feeding began. The Na2O 11 amounts of feed were equal to glucose 7.5 gr/day, CaO 9 Figure 1. Activated sludge acquisition 69 Journal of Ecological Engineering Vol. 18(3), 2017 Figure 2. Schematic diagram of the experimental setup RESULTS AND DISCUSSION formed in order to determine the concentration of volatile suspended solids in the aeration basin of MLSS testing measures the total concentration an activated sludge system. Mixed liquor volatile of mixed liquor suspended (non-soluble) solids in suspended solids data are critical in determining the aeration basin of an activated sludge system. the operational behavior and biological inventory The mixed liquor suspended solids (MLSS) data of the system. The filter used for mixed liquor sus- are critical in determining the operational behavior pended solids (MLSS) testing is ignited at 550°C and solids inventory of the system and it is used for 30 minutes. The weight lost on ignition of the to determine when to waste and/or recycle sludge. solids represents the volatile solids in the sample. In order to test the mixed liquor suspended Figure 3 shows the rate of MLSS and MLVSS. solids (MLSS) a well-mixed sample should be fil- During 28 days MLSS increased from 1.259 g/lit tered through a weighed filter. The residue left on to 1.299 g/lit and MLVSS increased from 1.257 g/ the filter is dried to a constant weight at a temper- lit to 1.295 g/lit. ature between 103 °C and 105 °C. The increase in Biochemical oxygen demand (BOD) and weight of the filter represents the total suspended chemical oxygen demand (COD) are two differ- solids of the sample. The size of sampling should ent parameters to measure how much oxygen the also be limited to a size the yields, no more than water will consume when it enters the recipient. 200 mg residue. After the mixed liquor suspended In both cases the oxygen-consuming substances solids value is determined a mixed liquor vola- are mainly of organic origin. These substances tile suspended solids (MLVSS) test may be per- should be reduced to a minimum in the waste- Figure 3. The rate of MLSS and MLVSS of activated sludge, during the test 70 Journal of Ecological Engineering Vol. 18(3), 2017 water treatment plant. Industries normally focus COD removal efficiency rate with the time in R1, more on COD and municipalities than on BOD the high decreases in COD concentrations occur removal. With a chemical treatment, removal of in the first 3 days. After that, the removal rate is COD is improved at basically all kinds of waste- linear. At the end of the test, the maximum re- water plants. The more particle-bound COD, the moval was 95% after 14 days. more efficient the removal rate. Our products can Figure 5 depicts shift of COD removal ef- separate some dissolved substances as well, but ficiency rates with time. Rapid slope increase in when the COD consists of small organic mole- COD removal efficiency rate with the time in R2, cules a biological treatment process is normally the high decreases in COD concentrations occur preferred. As shown in Table 2 in the 3 days, in the first 3 days. After that, the removal rate is COD removal efficiencies were from 61% to 81% linear. At the end of the test, the maximum re- in the R1, it was from 1.3% to 48% in R2 and moval was 97% after 21 days. 12% to 24% in R3. The reduction was observed Figure 6 depicts shift of COD removal ef- in the first week, equal to 95% in R1, 97% in R2 ficiency rates with time.